USB: dwc3: Add workaround for incorrect GUCTL register's default value

GUCTL[31:22] indicate the time period (in ns) of the reference clock
that is used to generate Isochronous Timestamp Packets (ITP).  This
value should be 8ns (125 MHz) by default.  But it is overridden with
0 on cores revision < 2.30a.  Fix this in software.

CRs-Fixed: 377846
Change-Id: I827540eb9d2f1ffc65b6f30200b6c0e575bc52d2
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>